Dental process and apparatus



July 23, 1963 A. R. CERVERIS DENTAL PROCESS AND APPARATUS 2 Sheets-Sheet 1 Filed Jan. 25. 1960 m 2 MR 0 e n m w A F u w m R..M H m w A 3 L m F/GJ FIG/b- July 23, 1963 A. R. CERVERIS DENTAL PROCESS AND APPARATUS 2 Sheets-$heet 2 Filed Jan. 25, 1960 FIG. 8

INVENTOR ALBERT R. CERl/fR/S FIG. 4

ATTORNEYS United States Patent 3,098,298 DENTAL PROCESS AND APPARATUS Albert R. Cerveris, 733 Washington Road, Pittsburgh, Pa. Filed Jan. 25, 1960, Ser. No. 5,088 7 Claims. (Cl. 3219) This invention relates to a process and apparatus for accomplishing an integrated occlusal equilibration. More specifically, this invention relates to a process and apparatus for accomplishing an accurate centric equilibration of upper and lower natural or artifical teeth.

This application constitutes a continuation-in-part of my earlier copending application Serial Number 802,102 filed March 26, 1959, now abandoned.

In the past, the equilibration of natural teeth has been accomplished by a spot-grinding procedure. This has involved the use of indicating means held between the closing upper and lower teeth of the patient to indicate the high spots. The closing has been accomplished by the manual manipulation of the lower jaw in an upward direction by the dentist, or by the patient, himself, tapping together his teeth on the indication means. In either of these manners, the indication means has made a showing of the high spots or premature contact areas which were later spot ground by conventional grinding means to reduce their height.

Using either of the procedures for indicating outlined above, I have found it is difiicult to record accurately the centric relation of the mandibular (lower) teeth with the maxillary (upper) teeth. Where premature contacts occur in the centric relation of the teeth, the lower teeth, when closing in to occlude with the upper teeth, will make a correctional shift of avoidance to prevent the irritating premature cont-acts from being made. This shift is involuntary to the patient. Thus, using the procedures above, I note an incorrect registration of premature confacts. The lateral corrective shift of avoidance will cause unoifending areas to be accidentally marked for reduc tion.

I have found that if vertical reciprocal vibrations are imparted to the mandible with sufficient frequency and intensity, there will be produced two fundamentally important results-first, the stimulation of the depressor muscles and the retrusion of the condyles of the mandible to produce correct centric relation; secondly, sufficient impact intensity to drive the mandible through the correct physiologic arc of closure while the depressor muscle complex is in force.

Retrusion of the condyles is essentially the key to the correct centric relation. When external elevating pressure is lightly applied to the mandible in the rest position, certain muscles, namely the supra and infrahyoid groups, the lateral pterygoids and elements of the platysma, will contract against the pressure. When the external elevating pressure is of sufiicient intensity, the mandible will automatically seek to brace itself. Because the depressor muscle action is in force, the mandible cannot brace itself by the occlusion of the teeth, so the bracing action can only be obtained with the retruded condyle heads in a braced position in the fossae. When the mandible, from the rest position, accepts the vibrations with the condyles braced and with the depressing muscles in force, the vibrations will drive the mandible through the depressing muscle action to tooth contact. When tooth contact is achieved under these conditions, the teeth will vibrate verticaily against each other in the correct centric occlusion. interferences to the correct centric occlusion may then be accurately recorded and removed.

Taking my development one step further, I have found that a perfect centric occlusion which is correctly integrated with the centric relation of the mandible can be ice 2 achieved without appreciably reducing cusp height by rapidly manipulating the mandible in a centric arc of closure with an abrasive substance applied to the occlusal surfaces. The results are far more accurate than those attained by conventional spot grinding techniques. Also there is a minimum reduction of desirable cusp height.

In the past, the equilibration of artifical teeth has included mounting the upper and lower arches of teeth or portions thereof in an articulator having means to move the upper and lower arches relative to each other in a complicated motion simulating the vertical and lateral travel of the patients condyle path. After mounting, Carborundum paste or the like has been disposed on the occlusal surfaces of the upper and lower teeth and the complicated relative motion has been repeatedly undergone to Wear down the offending prematurely contacting surfaces. This has often invloved substantial cusp height reduction without eliminatiing centric interferences.

I have concluded that there is a basic fallacy underlying the apparatuses of the prior art for accomplishing equilibration on artificial teeth. Simply stated, my conviction is that since mastication by humans essentially involves a shearing action with teeth moving in a centric path, and since the contacts not made during mastication are almost invariably when the teeth are in centric relation, we only need concern ourselves with the meticulous equilibration of force distribution in the centric occlusion. Thus, the relative motion of the upper and lower dental arches in the articulator should be in the centric path, that is vertically, up and down, without concern for any lateral excursions. This method permits integrated centric equilibration of the dental structure with a minimum reduction of desirable cusp height.

It is, therefore, an object of my invention to provide a process for accurately equilibrating upper and lower natural or artificial teeth without appreciably reducing cusp height.

It is a further object of my invention to provide an apparatus for accomplishing an accurate rapid and simple integrated equilibration of natural teeth Without appreciably reducing cusp height.

It is a further object of my invention to provide an apparatus for the accurate, rapid and simple integrated equilibration of artificial teeth Without appreciably reducing cusp height.

This invention embodies other novel features, details of which are hereinafter set forth in the specification and claims, and illustrated in the accompanying drawings, wherein:

FIG. 1 is an embodiment of the apparatus of my invention shown in use equilibrating natural teeth;

FIGS 1a and 1b show teeth in front elevation before and after accomplishment respectively of my process;

FIG. 2 is an elevation partly in section of an embodiment of the apparatus of my invention adapted for use in equilibrating natural teeth;

FIG. 3 is a top plan view of the embodiment of the apparatus of my invention shown in FIG. 2;

FIG. 4 is a front elevational view of a modification of the apparatus of my invention adapted for use in the equilibration of artificial teeth;

FIG. 5 is a side elevational view of the modification of my invention shown in FIG. 4;

FIG. 6 is a top plan view of a modification of .the apparatus of my invention shown in FIGS. 4 and 5;

FIG. 7 is a top plan view showing the clamping member of the modification; and

FIG. 8 is a sectional view taken on the line 8-8 of FIG. 7.

Apparatus for Equilibrating Natural Teeth Referring more specifically to the drawings, an emmodiment of the apparatus of my invention is shown in FIG. 1 and is generally designated 10. It comprises a handle 12 on the top of which is mounted (see FIG. 2) an electric field winding 14 surrounding a core member .16. Preferably the core member protrudes upward from the top of the winding. Secured to and running along the sides of the winding are a pair of metal strips 18 which at their upper end bend outwardly and then curve inwardly to provide a pair of spring arms. To the distal ends of the two spring arms are rigidly secured respectively the opposite ends of an armature plate 20. The plate is adapted to be responsive to the maguetie field immediately adjacent the upper end of the core member.

Secured rigidly to the upper surface of the armature plate is an upstanding stud 22. Preferably the stud is threaded. A chin rest or table 24 comprising a body of semi-rigid rubber or the like is provided. its upper surface is appropriately contoured and concave to receive in comfortable engagement the underside of a human chin as shown in FIG. 1. The bottom surface of the chin rest mounts a downwardly extending boss 26 having a central bore, preferably threaded. The bore receives threadedly the upstanding stud 22. A set screw may be provided in the boss to lock the stud and the chin rest in appropriate relation.

The electric field winding 14 and spring arms 18 are surrounded by a hollow plastic housing 28 apertured at the top to permit passage of the stud. The lower end of the housing is secured about the top of the handle 12 by appropriate means. Through the handle extends the lead wire to the electric field winding. An on-ofi switch 30 controlling the actuation of the electric field winding may be mounted in the handle for convenience. The lead extends out through the lower end of the handle through an appropriate frequency converter 32, to an appropriate power source.

Preliminary to the operation of the apparatus for equilibrating natural teeth shown in FIG. 2, is the applying to the occlusal surfaces of the teeth of an abrasive substance. Preferably this substance is a water-soluble, greaseless suspension of fine Carborundum. The lower jaw or mandible of the patient is then permitted to assume a physiological rest position. The apparatus is disposed vertically with the chin rest portion engaging the underside of the chin of the patient. The electric winding of the apparatus shown in FIG. 2 is then actuated with alternating electric current or direct pulsating electric current so that the armature plate 26? and the chin rest which it carries is vertically reciprocated at a relatively high speed. The vertical reciprocation imparts up and down vibrations to the patients jaw.

The operator then raises the apparatus, forcing the vibrating lower jaw upward. In so doing the patient will first sense the initial contact of the teeth of his lower jaw with those of his upper jaw. This initial contact will be audible to the operator. Because of the application of the abrasive substance to the occlusal surfaces of the teeth, the up and down vibrating of the lower jaw will cause a wearing of the prematurely contacting surfaces first. Upon hearing the audible initial contact, the operator does not raise the apparatus further, but works instead on this first contact. By improperly raising the apparatus above this first contact before it is abraded away, it is possible to displace the prematurely contacting teeth sutliciently to cause unofifending teeth to be ground simultaneously. This obviously would defeat the purpose of the technique completely. It will be understood that if the operator continues to hold the apparatus in elevated position, premature contacts will wear away and the secondary contacts may then be contacted also and wear so that if the process is continued long enough, the entire set of teeth will be equilibrated.

In actual practice it has been found that the length of time during which the individual patient is subjected to the vibration treatment must vary depending on the need and the fatigue factor. During treatment, the vibrations are applied intermittently, not continuously. The teeth are vibrated on the average of to seconds at a time. After a. few seconds rest, the vibrations may be reapplied for another 15 to 20 seconds. This has been continued intermittently over a period ranging from 15 minutes to minutes, depending on the patients fatigue point. Sometimes, before the equilibration is complete, the patient chooses not to continue the treatment but to rest and come back for subsequent treament at a later time.

I have discovered that in order to achieve an accurate equilibration, the vibration of the chin rest must be accomplished at a frequency of at least approximately times per second. By vibration, I mean a movement in one direction up or down. Therefore, a complete cycle, consisting of one movement in the upward direction followed .by one movement in the downward direction, under by definition of vibration will consist of two such vibrations or movements opposite in direction. I have selected this meaning of vibration to emphasize that movement in one direction is as important as movement in the other. The motion of the chin rest in the upward direction elevates the mandible, while the motion in the downward direction permits the depressor muscles to force the mandible downward. Thus, under my definition of vibration, 120 vibrations constitute 60 complete cycles. It has been found that if a lesser frequency of vibration is used, the patient very frequently disrupts the process of involuntary muscle action. This tendency to disrupt the process as vibrations are lowered in frequency varies from patient to patient. For some patients 80. vibrations per second, or 40 complete cycles per second, or even a lesser frequency will be a sufliciently rapid movement at which to conduct the process successfully without undesired involuntary muscle action. It is seen that such involuntary muscle action of the various jaw muscles could draw the jaw laterally in any direction to give false premature contact and result in inaccurate equilibration. The preferred frequency is 120 vibrations or 60 cycles per second.

Just as the vibrations must be rapid, they must not be too rapid. The upper limit varies according to the fre quency for each individual patient at which there is a reflex contraction of the elevator muscles which would disrupt the process. It is preferable that the vibrations not exceed 300 or cycles for most patients.

The equilibration process is completed by rinsing off or otherwise removing the layer of abrasive substance which has been applied.

It has been found that after the initial equilibration has been achieved, a natural reaction of the structure of the mouth will cause teeth to readjust slightly. Therefore, it is desirable to have a second equilibration session two or three weeks after the initial one.

In cases where there is a marked or pronounced contacting of the teeth in one or two local areas, before the integrated equilibration, it is sometimes desirable to accomplish some spot grinding with conventional grinding means. The apparatus or manipulator shown in FIG. 2 is helpful in this regard in that high spot indicating means such as wax can be applied to the teeth and the apparatus applied to the chin to cause the teeth to tap together, indicating accurately the pronounced premature contact. Once the areas are indicated, the spot grinding may be easily accomplished. Thus my apparatus is also useful as a means to record premature contacts or high spots when the mandible is disposed in centric relation. The bracing reaction of the mandible to the vibrations will constantly position the mandible in centric relation. Thus a more accurate recording of the location of premature contacts in the centric occlusion may be made.

FIGS. 1a and lb indicate .a pair of contacting teeth before and after equilibration under my process. It can be noted that there is substantially no reduction in cusp height, only an even wearing on the inclined surfaces of the teeth in the contacting areas. Arrows indicate the correction of traumatic occlusion.

Apparatus for Equilibrating Artifical Teeth The apparatus shown in FIGS. 4 through 8 has been designed for equilibration of artificial teeth using my process. It is generally designated 110 in FIG. 4. It comprises a base to which is secured an electric field winding 112 having a core 113 and supplied by power means as in the previous embodiment. Running up the opposite sides of the field winding are a pair of metal strips 114 which bell outwardly at the top and then curve inwardly to the upper ends. To the upper ends of the strips are secured the opposite ends respectively of an armature plate 116. To the top of the armature plate is secured an upstanding stud 118 which is preferably threaded at its upper end. A table 120 is provided which has a central downwardly extending boss 122 on the lower surface thereof. The boss has a central bore and is tapped and receives the upstanding stud in threaded engagement. A skirt or apron 124 may be secured about the periphery of the table to depend therefrom and protect and conceal the electric field winding.

As shown clearly in FIG. the table 120 engages means for holding the upper and lower arcs or portions thereof of artificial teeth. More specifically, means 126 for holding the lower arc comprise a backing member 128 having three downwardly extending legs 130 as shown in FIG. 8. The legs are axially bored from their lower ends up and the table 120 is apertured and countersunk from its lower surface to receive bolt-s securing the legs of the table.

At the rear end of the table are upstanding means 132 preferably a pair of spaced arms having adjacent their upper ends an interconnecting bridge 134. The upper ends as shown in FIG. 5 are enlarged and each has formed therein a horizontally disposed hole, the holes being in axial alignment. The holes are tapped and each receives from the outside a threaded pin 136. Each pin is pointed at its inner end as shown in FIG. 6.

A leaf 138 is provided and includes a thickened rear end area. The opposite sides of the enlarged rear end area are bored in axial alignment with the inner end of each bore tapered as shown at 149 in FIG. 6 to conform to the shape of the pointed pin 136. The leaf thus pivots on a horizontal axis between the two arms 132. Nuts 142 are applied to the threaded outer ends of the pin to engage the surface of the arms 132 respectively to lock the pins in the desired position.

The forward portion of the leaf carries means 126' for supporting the upper arch of the artificial teeth. This means similar to means 126, includes a backing member (not shown) having upwardly extending legs 130 in the shown embodiment somewhat shorter than the legs 130. The leaf 138 is bored and countersunk from above and bolts extend therethrough threadedly engaging axial holes in the legs 130'.

As shown in FIG. 7, a typical showing of the dental arch supporting means, each backing member 128 is engaged by a hinged clamp 144 comprising a pair of arms having hinge means 146 at the rear thereof. One of the arms of each clamp has pivoted to its forward end a bolt 148 while the other arm carries a slotted keeper 150. The bolt receives a thumb nut 152 as shown in FIG. 7 and the bolt is adapted to pivot into the slotted keeper after which the nut may be tightened to lock the clamp in position about the backing member.

As an alternative to the hinged clamp 144, a O-shaped clamp of bent spring steel may be used.

From FIG. 8, it will be noted that the cross section of each arm of the clamp includes a lower ridge 154 adapted to interfit with a groove 156 formed about the periphery of the backing member 128. The clamp also has an inwardly tapering upper wall 158. In use, the plastic arc of porcelain teeth is mounted in plaster of Paris having an outward flange on the base thereof. The outer flange fits inside and against the inwardly tapered wall 158 of the upper portion of the clamp as shown in FIG. 8 and when the thumb nut 152 is tightened, the arc of teeth or portion thereof is secured to the backing member 128.

In the use of the apparatus for equilibrating artificial teeth shown in FIGS. 4 through 8, the teeth are carefully mounted in the device in superposed relation established by means of the principles previously described in connection with the apparatus for equilibrating natural teeth. The occlu'sal surfaces are coated with an abrasive substance. The electric field winding is then actuated to commence vibration of the table 120. This Vertical vibration imparts an up and down movement to the lower arch of teeth while the upper arch is permitted not only to vibrate up and down but to flap about its pivot pins 136. The extent of the vibration and flap of the upper arch can be controlled to an extent by the hand pressure of the operator on leaf 138. Also means in the apparatus may be provided to regulate the intensity of the vibrations of the table 120. The effect of the motion is a wearing of the occlusal surfaces of the teeth which prematurely contact while the arches are invariably maintained in centric relation. Thus, the arches of teeth are equilibrated without appreciable reduction of cusp height. The process is completed by rinsing off the abrasive.

It will be understood that While full arches of teeth are shown held in the apparatus of FIG. 4, partial arches may be mounted similarly and subjected to the same equilibrating process.

As in the process for equilibrating natural teeth described above, the apparatus shown in FIGS. 4 through 8 may -be used to indicate for spot grinding certain prematurely contacting local areas of artificial teeth. This may be accomplished by putting a wax or other indicating means between the upper and lower arches and vibrating the dental structures for a moment. The wax will indicate where spot grinding is necessary.

It will be clear from the above description, that the process and apparatuses described represent an entirely new concept in equilibration. Where lbefore prematurely contacting surfaces of natural teeth were invariably spot ground painstakingly and invariably inaccurately, my new device permits the accurate equilibration of the entire mouth in a rapidly and easily executed manner. The equilibration of artificial teeth, previously damaging to desirable cusp height, is now, by the virtues of my development, not damaging.

While this invention has been shown in but a limited number of forms, it is obvious to those skilled in the art that it is not so limited but is susceptible of various changes and modifications without departing from the spirit and scope of the claimed invention.

I claim:

1. A process for accurately recording the contacts of upper and lower teeth when the mandible is disposed in centric relation, said process including the steps of disposing a recording substance on an ccclusal surface of the teeth and applying to the mandible from its rest position an intermittent elevating force at a frequency within about the range of 40 to cycles per second, said force raising the mandible up to a point at which tooth contact is first made.

2. A process for accurately equili'brating together upper and lower teeth situated in superposed relation, said process including the steps of disposing an abrasive substance on the occlusal surfaces of the teeth and applying to the mandible from its rest position an intermittent elevating force at a frequency Within about the range of 40 to 150 cycles per second raising the mandible up to a point at which tooth contact is first made.

3. A process for accurately recording the contacts of upper and lower teeth when the mandible is disposed in centric relation, said process including the steps of disposing a recording substance on the occlusal surfaces of the teeth, and applying to the mandible from its rest position an intermittent elevating force at a frequency of at least approximately 60 cycles per second raising the mandible up to a point at which a contact of such upper and lower teeth is first audible.

4. A process for accurately equilibrating together upper and lower teeth situated in superposed relation, said process including the steps of disposing an abrasive substance on the occlusal surfaces of the teeth and applying to the mandible from its rest position an intermittent elevating force at a frequency within about the range of 40 to 150 cycles per second raising the mandible up to a point at which -a contact of such upper and lower teeth is first audible.

5. A process for accurately equilibrating together upper and lower teeth situated in superposed relation, said process including the steps of disposing an abrasive substance on the occlusal surfaces of the teeth and applying to the mandible from its rest position an intermittent elevating force at a frequency of at least approximately 60 cycles per second raising the mandible up to a point at which a contact of such upper and lower teeth is first audible.

6. An apparatus for accurately equilibrating together upper and lower natural teeth without appreciably reducing cusp height, said apparatus including an electric field winding having a core member, means for actuating said electric field winding by supplying thereto an alternating electric current or a pulsating direct electric current whereby a magnetic field may be intermittently established adjacent the upper end of said core member, narrow resilient strip members each having an end portion secured to opposite sides of said electric field winding and a distal end portion supporting an armature member parallel to and in spaced relation with respect to the top of said core member when said armature member is free from the effect of said magnetic field and permitting reciprocating motion of said armature member only in directions vertical to the top of said core member responsive to said magnetic field, said armature having mounted thereon a chin rest having an appropriately contoured concave upper surface adapted to engage the underside of a patients chin said narrow resilient strip members each being bent outwardly and curved inwardly intermediate said ends thereof with respect to the'sides of said electric field winding andbiasing said chin rest against the chin of the patient when said armature is free from the effects of said magnetic field.

7. An apparatus for accurately equilibrating together upper and lower artificial teeth without appreciably reducing cusp height, said apparatus including an electric field winding having a core member, means for actuating said electric field winding by supplying thereto an alternating electric current or a pulsating direct electric current whereby a magnetic field may be established adjacent the upper end of said core member, means secured to opposite sides of said electric field winding supporting an armature member parallel to the top of said core member and permitting reciprocating motion of said armature member in directions vertical to the top of said core member responsive to said magnetic field, said armature carrying a table, the upper side of said table adapted to support securely at least a portion of a lower arch of teeth, said table carrying rigidly an upstanding member, a leaf pivotally secured to the upper end of said upstanding member by pivot means having a horizontal axis and means on the underside of said leaf adapted to support securely at least a portion of an upper arch of teeth in centric relation with said lower arch of teeth.

References Cited in the file of this patent UNITED STATES PATENTS 1,093,301 Vande Apr. 14, 1914 1,646,749 Gritman Oct. 25, 1927 2,064,418 Derringer Dec. 15, 1936 2,674,797 Skinner Apr. 13, 1954 2,863,216 Lichtman et a1. Dec. 9, 1958 

1. A PROCESS FOR ACCURATELY RECORDING THE CONTACTS OF UPPER AND LOWER TEETH WHEN THE MANDIBLE IS DISPOSED IN CENTRIC RELATION, SAID PROCESS INCLUDING THE STEPS OF DISPOSING A RECORDING SUBSTANCE ON AN OCCLUSAL SURFACE OF THE TEETH APPLYING TO THE MANDIBLE FROM ITS REST POSITION AN INTERMITTEN ELEVATING FORCE AT A FREQUENCY WITHIN ABOUT THE RANGE OF 40 TO 150 CYCLES PER SECOND, SAID FORCE RAISING THE MANDIBLE UP TO A POINT AT WHICH TOOTH CONTACT IS FIRST MADE. 